If X-Y = 3xy = 10, then the square of X + the square of y =?

If X-Y = 3xy = 10, then the square of X + the square of y =?

(x-y)²=3²
x²-2xy+y²=9
x²+y²=9+2xy=9+20=29

General score: x + 4 / x ^ 2-8x + 15, X-5 / x ^ 2 + X-12, x-3 / x ^ 2-x-20

x^2-8x+15=(x-3)(x-5) x^2+x-12=(x-3)(x+4) x^2-x-20=(x-5)(x+4)∴（x+4)/(x^2-8x+15)=(x+4)^2/(x-3)(x+4)(x-5)=(x^2+8x+16)/(x-3)(x+4)(x-5)（x-5)/(x^2+x-12)=(x-5)^2/(x-3)(x+4)(x-5)=(x^2-10x+25)/(x-3)(x+4)(x-...

Divide 3 / 4, 2 / 3 and 2 / 5

45 / 6040 / 6024 / 60 supplement: because the denominator 4, 3 and 5 do not have the simplest common divisor, the common denominator 60 can be obtained by direct multiplication; 60 / 4 = 15, 3 / 4 = 45 / 60,; similarly, 40 / 60 24 / 60 can be obtained

Four out of twelve equals one out of five, 21 out of 16

Four out of twelve equals one-third, five out of 15, seven out of 21, 16 divided by 48

It is known that P: x2-8x-20 ＞ 0, Q: x2-2x + 1-a2 ＞ 0. If P is a sufficient and unnecessary condition of Q, the value range of positive real number a is obtained

p: X ＜ - 2 or ＞ 10, Q: X ＜ 1-A or X ＞ 1 + a ∵ where p is a sufficient and unnecessary condition for Q, ∵ 1 − a ≥ − 21 + a ≤ 10, that is, 0 ＜ a ≤ 3

Simple calculation of 13 and 14 / 13 × 13 / 1

13 and 13 / 14 × 1 / 13
=13 × 13 / 1 + 14 × 13 / 1
=1 + 1 / 14
=1 and 1 / 14
Have a good time

The vertex of parabola C is at the origin, the focus f coincides with the right focus of hyperbola x23 − y26 = 1, and the straight line L passing through point P (2,0) with slope 1 intersects with parabola C at two points a and B. (1) find the chord length | ab | & nbsp; & nbsp; & nbsp; (2) try to judge the position relationship between the circle with chord AB as diameter and the parabola

(1) The right focus of hyperbola is f (3,0), which is also the focus of parabola Let a (x1, Y1), B (X2, Y2), from y = x − 2Y2 = 12x, we get x2-16x + 4 = 0 (4 points) | chord length | ab | = (1 + 1) (162 − 4 × 4) = 430 (6 points) (2) the coordinates of the middle point of the chord are X Middle = X1 + X22 = 8 & nbsp;, & nbsp; & nbsp; y middle = x middle − 2 = 6 The center of a circle with diameter AB is (8,6), the radius r = 230, and the directrix is x = - 3. The distance between the center of the circle and the directrix d = 8 + 3 = 11 ＞ 230 = R. the circle is separated from the parabola (12 points)

Simple calculation of 8 / 5-7 / 8 + 2 / 5-1 / 8

Hello!
Simple operation——
Eight fifths - seven eighths + two fifths - one eighth
=(5 / 8 + 2 / 5) - (7 / 8 + 1 / 8) [additive commutative law]
=10 out of 5-8 out of 8
=2-1
=1
I wish you progress in learning, hope to adopt, thank you_ ∩)O~

Compare the formula 3x ^ 2-2x-7 and 4x ^ 2-2x + 7

(4x²-2x+7)-(3x²-2x-7)
=4x²-2x+7-3x²+2x+7
=x²+14>0
So 4x & # 178; - 2x + 7 > 3x & # 178; - 2x-7

The school assigned 360 science and technology books to class A, class B and class C. class A's 1 / 2 equals class B's 1 / 3 equals class C's 1 / 4. How many books did class A, class B and class C get

According to the meaning of the title: Class A, class B and class C share the number of science and technology books: 2:3:4, so class a score: 360 divided by (2 + 3 + 4) x2 = 80, class B score: 360 divided by (2 + 3 + 4) X3 = 120, class C score: 360 divided by (2 + 3 + 4) X3 = 120